Philip J. Dolan (Editor), Capabilities of Nuclear Weapons, Stanford Research Institute, Defense Nuclear Agency Effects Manual 1, DNA EM 1, 1972, with page updates Change 1 (1978) and Change 2 (1981). Declassified in 1989 with some deletions. Note that this is Part 1, Phenomenology, 835 pages. There is a separate Part 2, Damage Criteria, which gives data on damage and effects caused by the various phenomena. This manual was first issued in July 1951 as TM 23-200, Capabilities of Atomic Weapons. It was renamed Capabilities of Nuclear Weapons in 1964. The current version is 22 volumes long (Harold L. Brode's 1992 edition), with a separate volume for each chapter. A condensed summary of declassified data was issued in 1996: John A. Northrop's Handbook of Nuclear Weapon Effects : Calculational Tools Abstracted from EM-1. Revisions continue. Discussion: http://nukegate.org/
http://glasstone.blogspot.co.uk/
See also: The effects of the atomic bomb on Hiroshima, Japan (the secret U.S. Strategic Bombing Survey report 92, Pacific Theatre) located at: http://archive.org/details/TheEffectsOfTheAtomicBombOnHiroshima
The EM-1 manual's limitations are discussed at https://www.nukegate.org/ In particular, it was recognised by John von Neumann and others during the Manhattan Project that the act of doing work on a city absorbs blast energy, and Penney later proved this to be the case in both Hiroshima and Nagasaki by measuring the reduction in peak overpressure (from damage done by crushed petrol cans, etc) compared to British nuclear tests on unobstructed terrain at Maralinga (Penney et al., 1970). The energy absorbed from both the overpressure and dynamic pressure loading of a blast wave in pushing (i.e. oscillating in the elastic range) and/or damaging buildings (i.e. the larger soak up of energy in the bigger plastic deformation range, particularly for ductile buildings with steel frames or reinforced concrete) is readily calculated since a deflection of a building's centre of mass by "x" metres requires energy E = Fx = PAx, where P = pressure and A = area. The Northrop 1996 book gives the required data for calculating this energy for a range of buildings on pages 521-5, e.g. Figure 15.7 (where energy absorbed is proportional to the area under the load-ductility ratio "curve") and Table 15.6 (giving oscillation periods, static yield resistance pressures, and ductility ratios for damage for 15 kinds of building). The maximum deflection of a building at a particular distance is calculated from the equation 6.105.1 on page 283 of the 1957 edition of Glasstone's Effects of Nuclear Weapons (not present in later editions!), or from Bridgman's 2001 Introduction to the physics of nuclear weapons effects (DTRA limited edition). Whereas Northrop's 1996 EM-1 Fig. 15.20 shows that a multistorey reinforced concrete building is 50% likely to collapse at 2.7 km ground range from a 1 megaton surface burst (on unobstructed desert terrain), this range could be reduced massively in a real city where intervening buildings absorb most of the blast and radiation (a fact ignored in Western nuclear test data analysis such as Glasstone and EM-1).
EM-1 is therefore more applicable to military targets in open terrain than civilian cities, although it does contain some corrections for shielding in typical real terrain. For example, Northrop's 1996 EM-1 Fig. 16.18 shows thermal exposures in a 1 metre high wheat stand, 4 km from a 550 kt burst at 400 metres altitude: the "theoretical" (Glasstone and Dolan type) free-field thermal exposure is 40 cal/cm^2, but this falls to just 0.2 cal/cm^2 at ground level, showing a shielding effect. A city skyline is even more effective at this sort of shielding, and Figs. 16.16 and 16.17 shows that forests also provide significant shadowing for wide angles, unless the burst is directly overhead. For example, for 1,100 trees/acre of spruce trees there is zero exposure if the fireball's elevation angle above the horizon is 20 degrees or less! Under such conditions, dry leaf litter on the forest floor will not burn regardless of the "free field" exposure calculated from unobstructed line-of-sight assumptions by Glasstone and Dolan! This shadowing problem has obvious major implications for both "firestorm" and "nuclear winter" (firestorm soot cloud) anti-nuclear propaganda efforts used to justify our disarmament.
Evidence of such resistance of forests to nuclear weapons thermal radiation is in Figs. 6.24a and 6.24b in Glasstone's 1957 Effects of Nuclear Weapons (photos removed from later editions, but identified in the declassified film Military Effects Studies on Operation Castle, as well as Fons and Storey's report Operation Castle, project 3.3, blast effects on tree stand, Figs. 3.2 and 3.8): the former shows the unburned forest stand at 9,300 ft from ground zero on Uncle Island, Bikini Atoll, for 110 kt Castle-Koon in 1954 after 3.8 psi peak overpressure, and the latter shows the unburned forest stand at 62,500 ft from ground zero on Victor Island, Bikini Atoll, for 14.8 Mt Castle-Bravo in 1954 after 2.4 psi peak overpressure. Some blast damage occurred to the trees, but there was no fire. Real world shadowing, and realistic 50-80% humidity of most targets near water (such as most coastal cities, or cities beside large lakes or rivers like Detroit and London), reduces ignition risks contrary to data from low-humidity Nevada tests such as Encore in 1953 (19% humidity!).
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Secrecy classification and limited distribution versus the need for widespread understanding of the facts affecting national security in order for democracy to function, and also in order to allow a wide base of critical review and feedback to eliminate errors and misunderstanding which do often proliferate through closed-door groupthink "established wisdom Bible" bias:
(1) The USA disarmed all of its dedicated tactical W79 neutron bombs in 1992, but as a CIA report and more recent data on the history of 1960s Russian nuclear isentropic compression systems prove (a system developed and successfully tested in four shots of Operation Dominic by Livermore lab., USA in 1962, but then discarded), in this archive page compendium shows, Russia has thousands of neutron bombs. The 1996 Northrop EM-1 data on two yield ranges of neutron bomb output and neutron induced activity in European soil is therefore NOT giving away USA weapons effects data (USA doesn't have these weapons anymore!!), but rather RUSSIAN weapons effects data, purely of use for Western civil defense if and when Russia uses its tactical nuclear weapons to "defend" seized European territories! There is ZERO justification for keeping this data secret.
Likewise for EMP threats from Russia. Russia tested such bombs in 1962 with full scale 1000km power line exposure, but WE DID NOT DO THIS IN OUR TESTS, which provided less data because many instruments were mis-calibrated due to a failure in theoretical understanding in 1962. Russia published their data for North Korea, Iran, et al., to use. It is no use trying to limit taxpayer funded Western nuclear effects data from being used to help safeguard the West from Russia. THAT IS ACTUALLY PRO-TERRORISM, NO MATTER WHAT PRO-RUSSIAN "ARMS CONTROLLERS" RANT. It's as pathetic as supporting unilateral nuclear disarmament with faked open terrain blast and radiation data for use for cities in the disproved delusion that such tactics improve, rather than degenerate, our security.
(2) The examples above demonstrate blast and thermal radiation exaggeration problems for nuclear deterrence. The Russians, Chinese, and several other countries have conducted atmospheric tests and have their own sources of nuclear effects data. In addition, as the documents stored in this archive page demonstrate, the originally secret Western fallout patterns compendium, DASA-1251 (nuclear test fallout data from USA, UK, and French shots), contained one "GOOD" (but actually FALSE) land surface burst fallout for the typical yield range of modern MIRV warheads: the 110 kt Castle-Koon shot (the fallout went over most of Bikini Atoll, being fired on an island at the south of the Atoll when the wind was blowing generally towards the north, over islands and barges in the lagoon).
This SECRET error was then used to falsely "justify" many fallout models, such as SIMFIC, in limited distribution reports which nobody could see let alone debunk! After it was declassified, we found a serious error, exposed at nukegate.org in 2006: it massively exaggerates the actual fallout. The original error comes from the poorly checked source document, Operation Castle's weapon test report WT-915, which contains huge errors in the distance scale of Bikini Atoll for the Castle series, and which was simply copied into DASA-1251 in the 1960s without being checked or corrected! This kind of mistake could exist elsewhere, where somebody makes an original mistake which is then copied and used to "prove" something that is totally false in nuclear deterrent capabilities. We need openness or we are living in a dictatorship that might as well be ruled by some Stalinist shoot-the-messenger state.
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Selected relevant background reports have also been added in response to Russian nuclear threats to escalate its Ukraine invasion, which could result in "tests" or demonstration strikes at high altitude to cause EMP effects, or even low altitude air burst tactical nuclear weapons under cover of claiming Ukraine was responsible for attacking itself. Remember that Putin tried to blame the UK for the 2018 killing of Dawn Sturgess with Novichok, and Putin also denied the radioactive polonium 210 attack in London in 2006. Nuclear weapons launched by SLBM from submarines hidden in the ocean would not immediately disclose their origin, particularly if detonated at high altitude (although there is an AWE originated geomagnetic EMP unfold computer program - included in a report by John S. Malik uploaded within these documents - that allows a satellite EMP detector to be used to determine the gamma pulse of the weapon, which would fingerprint the weapon design from the relative sizes and rates of rise and fall of the primary and secondary stage gamma outputs, and the time delay for secondary stage ignition).
The West needs to be ready for Russian surprise tactics of their preferred Wang Jungze sort: "Deceive. Attack weak targets. Kill with a borrowed knife. Wait until the enemy tires of defense. Kick him when he is down. Use diversion tactics like noises in the East, when attacking from the West." Therefore, preparing only to deter an all-out nuclear attack ensures this enemy attempts to use other tactics, and it already has 2000+ dedicated tactical nuclear weapons, a vast tactical superiority.
Any future, openly-published, Glasstone and Dolan "Effects of Nuclear Weapons" or Northrop EM-1 edition should not only finally correct free-field blast and radiation effects for "concrete jungle" attenuation by a modern city, but should focus primary attention on the wide range of very different nuclear attacks, including tactical military attacks like a nuclear Pearl Harbor, or battlefield neutron defense, and the risk of high altitude EMP or anti-satellite attacks.
Keeping nuclear test data secret plays into the hands of those who wish to ignore or exaggerate certain kinds of attack for disarmament propaganda to aid an enemy, a problem that occurred in 1920s and 1930s Britain when all-out gas war was falsely hyped as a certainty in future war. The popular media proved to be just as much a vehicle for gas war deceit and propaganda then as it is today with the nuclear war. It realises that most people don't want to think about it, so it joins the chorus in trying to shoot the messenger, to make key facts appear "unthinkable". In the past this approach led to the biggest world war in history, so it is deplorable that the same tactics are being used again. Only by credible deterrence of the kind of invasions that set off both world wars (the invasion of Belgium in 1914, of Poland in 1939) and military attacks like Pearl Harbor in 1941, can we prevent the escalation to world war. Retreating to Lord Noel Baker's February 1927 BBC radio propaganda lying that "all experts are agreed" that all-out gas war (or nuclear) necessitates disarmament, is a certain road to another world war.
All of this data should have been published to inform public debate on the basis for credible nuclear deterrence of war and civil defense, instead of allowing enemy anti-nuclear and anti-civil defence lying propaganda from Russian supporting evil fascists to fill the public data vacuum, killing millions by allowing civil defence and war deterrence to be dismissed by ignorant "politicians" in the West, so that wars triggered by invasions with mass civilian casualties continue today for no purpose other than to promote terrorist agendas of hate and evil arrogance and lying for war, falsely labelled "arms control and disarmament for peace": "Controlling escalation is really an exercise in deterrence, which means providing effective disincentives to unwanted enemy actions. Contrary to widely endorsed opinion, the use or threat of nuclear weapons in tactical operations seems at least as likely to check [as Hiroshima and Nagasaki] as to promote the expansion of hostilities [providing we're not in a situation of Russian biased arms control and disarmament whereby we've no tactical weapons while the enemy has over 2000 neutron bombs thanks to "peace" propaganda from Russian thugs]." - Bernard Brodie, pvi of Escalation and the nuclear option, RAND Corp memo RM-5444-PR, June 1965.
Democracy can't function when secrecy is used to deliberately cover-up vital data from viewing by Joe Public. Secrecy doesn't protect you from enemies who independently develop weapons in secret, who have large enemy networks in your labs even in the manhattan project during WWII and long after that:
"The United States and Great Britain resumed testing in 1962, and we spared no effort trying to find out what they were up to. I attended several meetings on that subject. An episode related to those meetings comes to mind ... Once we were shown photographs of some documents ... the photographer had been rushed. Mixed in with the photocopies was a single, terribly crumpled original. I innocently asked why, and was told that it had been concealed in panties. Another time ... questions were asked along the following lines: What data about American weapons would be most useful for your work and for planning military technology in general?"
- Andrei Sakharov, Memoirs, Hutchinson, London, 1990, pp225-6.
Correction to Dolan's 1972 DNA-EM-1 forest blowdown data: Northrop's page 617 (section 18-3 of EM-1), Table 18.1, footnote c states that DNA-EM-1's Chapter 15 mistakenly reported tree girth (i.e. Pi or ~3.14 multiplied by the mean diameter of the tree measured 1 m above the ground) as the diameter, for tree types IVa-1 and IVb. The corrected average diameters for tree types IVa-1 and IVb are 13 and 11 inches, respectively.
It's also worth noting that there's an improved model of the blast wave precursor in Northrop's 1996 book. Northrop gives a semi-empirical means of predicting blast wave precursor waveforms in "Section 2.2 Air blast over real (non-ideal) surfaces" (pages 54-68). Computer calculations (Figures 2.72 and 2.73) indicate that for tactical nuclear weapons of 10 and 100 kt yield (approximately the range of most Nevada nuclear tests with strong precursors, where the largest air burst was Plumbbob-Hood at 74 kt), the thermal energy absorbed by a desert causes a fully developed hot dust cloud precursor with twice the classical shock speed. If height of burst is scaled to 1 kt (by the cube-root of yield scaling), this maximum precursor blast effect occurs for a burst height of 75-100 metres, and at a ground range of 225 metres from ground zero (as scaled down to 1 kt), where the dynamic pressure impulse reaches 2.0 psi-seconds (again, as scaled down to 1 kt yield). Figures 2.83 and 2.84 summarize data for the parameters needed to construct precursor blast waveforms.
Yet another example of the groupthink delusion resulting from MAD strategic deterrence hogwash is Western single-primary warhead nonsense (debunked at nukegate.org): Russian double-primary nuclear weapons development and their implications for modern Russian neutron bombs (i.e. low yield cleaner bombs for "peaceful uses" like deterring invasions, or deterring legal re-occupations of illegally seized territory) have been declassified by Russia. We have placed a summary of this data on this archive compendium, taken from nukegate.org analysis of translated original Russian nuclear lab films, reports and declassified documentation. The older single primary designs used in the West dating from an original test in late 1952 require a tritium and deuterium gas capsule in the secondary stage if the total yield is very low, making them expensive and in need of regular tritium replacement (half disappears by radioactive decay each 12.3 years!).
Trutnev's double-primary, double-approach Russian system, which didn't need foam to slow and disperse x-rays into "shadows" on the far side of the secondary, was first tested 23 February 1958, has obvious much better isotropy and so doesn't require the Western channel foam filler. Foam in UK and USA designs was used for x-ray diffusion to make a spherical secondary isotropically exposed to x-rays for compression (this problem was why Teller only used axial compression in the original foamless Teller-Ulam based Mike device of 1952 and other sausage or cylindrical secondary devices). It turned out that America peremptorily discarded such ideas (despite the original 1951 Teller-Ulam paper suggesting that more than one primary stage may be used!), and has always used only a single primary for groupthink delusion reasons, never even testing the Russian idea. But the double-approach makes it far more efficient on a yield-to-mass basis at compressing the secondary, thus cheapening and cleaning up the secondary design because you get better compression and don't need oralloy or tritium-deuterium boosting. Russian information suggests that with the dual approach (two primaries, one each side of the secondary) and isentropic compression (using a foam coating on the secondary stage, etc.), it is possible to obtain compressed gaseous deuterium fusion without tritium, something impossible with the smaller compressions of heavy oralloy secondary shock compression systems because the D+D fusion cross section is about 100 smaller than that for D+T.
Thus Trutnev's double primary system was more efficient at compression because it didn't need foam to slow and disperse x-rays into "shadows" on the far side of the secondary. So it was scaled down in the 1960s for cleaner low yield weapons, thus yielding enhanced neutron effects without needing tritium gas in the secondary stage (with the better compression in Trutnev designs, you can use a Li6D secondary even at low yield). Therefore, Western secrecy, even in weapon design, is a fallacy if the enemy is way ahead of you; then the secrecy stamp is just being used to dogmatically cover-up a scandal, and perpetuate your own expensive mistakes of ideology, which hardens into an orthodoxy of rigor-mortis.
For this very reason, Edward Teller was constantly complaining during the first Cold War that there was too much conformity in Western nuclear warhead design, that semi-empirical computer models based on one type (single primary) of design were being used to prevent the exploration of totally new ideas, etc: you can't get backing to test anything at extreme variance with "established wisdom". Every new Western design must be an incremental improvement on a previously validated Western design (because it must be evaluated using semi-empirical computer codes based on the single-primary framework of previous designs); thus, every "new" idea is limited perforce to containing the basic two-stage, single-primary assumption of previously tested designs as their basis. A "radical" design is one which changes the design of the primary or the secondary, but not one which changes the entire framework of design by introducing a second primary stage! Dogma is self-perpetuating, as it is in the routine development of physical theories (where every new theory must contain the previously validated theory as a subset, rather than being completely radical in which the previous theory is shown to just be a approximation contrived to fit the data and extrapolate a little). Declassification won't allow Russia to do anything if they have tested better designs already, and they can't afford Western designs that contain exorbitant amounts of tritium and oralloy.
Secrecy-cleared UK thermonuclear warhead historian Lorna Arnold and her assistant Katherine Pyne in their 2001 book "Britain and the H-Bomb" summarized Atomic Weapons Establishment secret history of UK thermonuclear warhead design tests up to the early interchanges of H-bomb data with America, in 1958. That book's information clarifies beyond any doubt the role of plastic foams in dispersing x-rays in the British type of weapon with an isotropically compressed spherical secondary stage, as opposed to the USA use of foam as simply a "radiation mirror" to re-radiate soft x-rays onto the cylindrical Teller Sausage secondary stage requiring only axial compression. Comparing this information to declassified double-primary Russian nuclear warhead design data conclusively confirms the relative merits of the different approaches. This information should be available to inform public debate on whether we have a nuclear deterrent that is efficient and cost effective, or whether a secrecy obsessed groupthink culture is used to drive warhead design into an expensive, inefficient, incredible dead end in the West, as contrasted to Russian H-bombs.
"The Halliard 1 warhead - a triple bomb [fission primary "Tom", x-ray imploded fission second spherical stage "Dick", and x-ray imploded third spherical stage "Harry" containing a spherical fissile core surrounded by a layer of lithium deuteride fusion fuel and an outer ablator shell of fissionable U238] - excited technical interest ... The American scientists, Cook noted, used a cylindrical second stage, which the Americans considered more amenable to calculation. (This was surprising to the Aldermaston scientists; it was partly because of the difficulties of computation and their lack of computing power that they had decided on spherical secondaries which, despite their limitations, reduced the need for complex implosion calculations.) ...
"K. V. Roberts, the [UK Atomic Weapons Research Establishment] theoretical physicist, recorded his impressions after the meeting: 'US double bombs are like ours - Tom -> radiative implosion -> Dick. But ... their Dick is cylindrical not spherical ... We've always considered that with a spherical Dick a slight difference of time or pressure over the outer surface of Dick is unimportant and have not tried to correct for this. But with a cylindrical design the different sections of the Dick implode essentially independently and ... it is essential to calculate the pressure time curve accurately for several points along the axis and to allow for variation'.
"Teller ... thought cylindrical geometry was the natural geometry to use; it had the advantage of allowing a greater volume of material to be imploded in a case of given dimensions. Case weights were lower in American bombs, yet calculated compressions were greater. ... the American designs were not very superior to the British; their superiority had been achieved by careful optimisation of a design which offered more freedom."
- Lorna Arnold, "Britain and the H-Bomb", Palgrave, 2001, pages 208-209 (Report by UK Atomic Weapons Research Establishment's Deputy Director Sir William Cook et al. on the Second UK-USA warhead designs exchange meeting, held at Sandia, 19 September 1958).
This quotation compresses a lot of previously top secret general thermonuclear design information, debunking nonsense and explaining differences in thinking about the drawbacks with computer models and with Teller's original 1946 cylindrical shaped fusion superbomb computational dogma. Both the UK and Russia went straight in with spherical secondary stages, now quid pro quo in Western compact MIRV warhead design. However, Arnold traces in detail how this amazing divergence in USA and UK approaches developed. Adding this to declassified US and Russian nuclear warhead design data, we get a complete understanding of the basic principles of evolution for all of the employed nuclear design options. (This information is entirely in the public domain, and is all available already to our adversaries.)
The basic facts of fission and fusion had been discovered even before WWII. For example, in 1937, Ernest Rutherford suggested the fusion of deuterium and tritium in his last published paper, yielding 5 times the energy of the deuterium-deuterium fusion reaction and with a cross-section (proportional to reaction probability) approximately 100 times greater (for typical nuclear explosion temperatures). After the discovery of uranium fission in Nazi Germany in 1938, the first actual suggestion to initiate a H-bomb using the explosive fission of uranium-235 was made by the Japanese physicist Tokaturo Hagiwara, at Kyoto University in May 1941. In May 1944, Manhattan Project physicist John von Neumann suggested placing deuterium and tritium gas inside a hollow fission bomb core to "boost" the efficiency, since 80% of the 17.6 MeV of energy per fusion would be released as 14.1 MeV kinetic energy neutrons, which would double the percentage of atoms fissioned, doubling the yield.
In April 1946 while British physicists were still contributing to Los Alamos (including Penney and Tuck, who both made essential nuclear weapons effects measurements at the first postwar American nuclear weapon tests, Operation Crossroads at Bikini Atoll), a secret Superbomb Conference was held at Los Alamos, attended by 31 physicists, including two British Mission to Los Alamos physicists who later worked at Harwell, UK, namely Egon Bretscher and the infamous spy Klaus Fuchs. Bretscher made calculations of deuterium-tritium fusion, while Fuchs jointly patented (with John von Neumann) the 28 May 1946 thermonuclear weapon design, which invented a way get a gun-type uranium-235 fission bomb to initiate fusion in a large mass of deuterium, by using an intermediate stage consisting of a x-ray radiation-imploded beryllium oxide capsule containing a mixture of deuterium and tritium. In August 1946, Teller proposed a spherical external boosting system with alternating layers of fission and fusion fuels, called the "Alarm Clock"; as for von Neumann's internal boosting system, the "Alarm Clock" would use neutrons from fusion reactions to boost the efficiency of the fission reaction in implosion systems.
In the period 1946-9, the Cold War intensified as wartime collaboration turned to confrontation; the Churchill's term "Iron Curtain" signified the Russian enforced separation of its occupied territories in Eastern Europe (including half of Germany) from the West. Finally, Russian tested a nuclear weapon in August 1949, and in response the American hydrogen bomb project was mentioned on TV on 1 November 1949. The hydrogen bomb debate quickly gripped the American media, but it was Fuchs' confession on 27 January 1950 of spying for Russia from 1942-9 which prompted the American atomic energy "General Advisory Committee" to conclude that Fuchs had probably given his and von Neumann's secret beryllium oxide x-ray imploded deuterium and tritium bomb design patent to Russia, as well as the fission bomb they tested in 1949. On 31 January 1950, President Truman publically announced that he was directing the US "Atomic Energy Commission to continue its work on all forms of atomic weapons, including the so-called hydrogen or superbomb."
In consequence, two thermonuclear tests were soon planned for early 1951: "Greenhouse-Item" (von Neumann's fusion neutron "boosted" core, with double the yield of an equivalent bomb lacking the deuterium and tritium core gas) and "Greenhouse-George" (George Gamow's adaptation of the physically separated x-ray imploded beryllium oxide cased fusion capsule, but using a special cylindrical implosion uranium-235 weapon, rather than the gun-type weapon in the Fuchs-von Neumann patent). But on 25 June 1950, communist North Korea invaded South Korea in the first "hot" proxy war between East and West, leading to General MacArthur's calls for tactical nuclear weapons. As a result, tactical nuclear weapon tests were held in the Nevada desert to prepare troops for nuclear warfare.
In February 1951, Stanislaw Ulam suggested a brilliant way to get much higher yields from nuclear weapons without requiring fusion reactions or massive conventional explosives to compress cores: simply use energy from one small fission bomb to compress another physically separate fission core, located within the same reflective outer casing. Edward Teller, whose own uncompressed superbomb idea had failed under calculation, then quickly adapted Ulam's idea by pointing out that the second fissile ore could be replaced by layers of fusion fuel and fissionable material, to achieve a compact, efficient thermonuclear weapon. The resulting "Teller-Ulam" report was issued on 9 March 1951. Rapidly, Teller went further, designing the first American "Sausage" secondary stage, a rod ("spark plug"), of fissile material in the core of a cylinder of fusion fuel, with an outer x-ray ablator of natural uranium.
Numerous articles and books contain claims made by Horward Morland, Chuck Hansen, et al., that Teller's idea is for primary stage x-rays to heat up "polystyrene" surrounding the thermonuclear stage, and for the "hot plasma of polystyrene" to then compress the thermonuclear stage. This is false because the energy of the primary stage x-rays is so low they would not penetrate more than a few millimetres into polystyrene, and in any case the density of the resulting plasma shock wave would be far below the density of the uranium pusher or jacket of the thermonuclear stage, so any compression would give rise to severe Rayleigh-Taylor instability (which occurs when a low density fluid exerts pressure on a higher density fluid).
Teller's actual idea (mentioned in the actual wording of the title of his and Ulam's 9 March 1951 paper), was polystyrene as a "radiation mirror," a layer inside the outer casing (not filling the entire radiation channel), to re-radiate ("mirror") primary stage x-rays hitting that lining, on the secondary stage.
Later, in British and compact American warheads when spherical secondary stages - requiring isotropic compression - replaced cylindrical Sausages in American warheads, especially low density plastic foams were indeed then used to fill the entire radiation channel to deliberately disperse x-ray energy into the "radiation shadow" on the far side of the secondary stage. But this is not to be confused with Teller's 1951 "radiation mirror".
Klaus Fuchs sold Russian agent Feklisov the Teller's April 1946 superbomb conference data and his and von Neumann's later beryllium oxide cased x-ray imploded fusion capsule patent, etc., in illegal meetings on 28 September 1947 and 13 March 1948. Russian's Sarov nuclear weapons physicist Goncharov stated that Fuchs: "handed over materials of paramount importance. Included in the documents was new theoretical information pertinent to the superbomb ... the two-stage configuration operating on the radiation implosion principle ... with a beryllium oxide tamper ...", which was translated into Russian and given to Beria, Molotov and Stalin on 20 April 1948.
While Stalin literally had the top secret American H-bomb secrets in his hands on 20 April 1948 courtsey of Fuchs, Penney had been busy preparing for Operation Crossroads, and had not attended the April 1946 Superbomb conference at Los Alamos. The two British Mission to Los Alamos physicists who had attended it, Fuchs and Bretscher, gave their notes to their chief, Sir James Chadwick (discoverer of the neutron). Chadwick then in May 1946 wrote a secret-classified British report called "The Superbomb", containing a schematic diagram of a three stage heavy-cased weapon, in which x-rays from a gun-assembly fission weapon "detonator" compresses a physically separate "primer" (containing tritium and deuterium), which in turn compresses a third stage "booster".
In August 1955, Penney held a meeting in his office to give new information to staff members John Ward, Bryan Taylor, William Cook, and Keith Roberts, where he "revealed what he thought he knew so far - that the H-bomb had a primary and a secondary, that the secondary was in two pieces, and that [neutron] shielding was required. ... On the basis of this information, Ward recalls, he was asked to 'come up with something'." Ward then spent the next four months in Aldermaston independently developing his "Harry" version of Teller's Sausage design, a 1 megaton yielding, 1 m long cylindrical thermonuclear stage with a central fissile "U235 rod" or spark plug which would give a yield of 100 kt (thus 10% fission yield) surrounded by lithium deuteride, which would provide 900 kt (thus 90% fusion yield).
This is in Keith Roberts' report, "An elementary theory of detonations I", AWRE TPN 123/55, dated December 1955 (UK National Archives Discovery catalogue reference: ES 10/173). Roberts' report on Ward's theory, however, noted that his cylindrical Harry would be "initiated at one end" (the end closest to the Tom or primary) and "it was necessary for neutrons to diffuse ahead quickly enough to keep up with the pressure pulse [as it propagated along the cylinder] if the [fusion burn] wave was to be maintained ...".
On 2 December 1955, a H-bomb progress meeting at AWRE Aldermaston by Penney and his deputy Cook was attended by Corner, Pike, Ward and others. Ward and Corner gave differing accounts of the meeting to historian Lorna Arnold. According to Corner: "Cook said, 'Well, does anybody know how it's done?' There was an embarrassed silence for two or three minutes, and then Ward drew a staged device - including a primary - on the blackboard ... Cook asked about the [neutron] shielding. Ward had not had time to calculate the shielding. Another deadly silence: then Penney said, 'Well this is too much like a piece of clockwork. If this were wartime we might consider something along these lines.' The drawing was rubbed off the blackboard ... Soon after ... there was another meeting to which Ward was not invited. A week later ... [Ward] told Cook he was leaving and returned to the United States. Ward had already been talking to Pike and Roberts about radiation implosion, and had suggested to the latter a calculation ... Roberts did it in a few days ... Ward ... was 'quite impressed'."
Ward did contribute in that sense, and by complaining openly in a 1985 letter to Thatcher (30 years later) about his treatment by Penney, he did eventually ensure that the relevant details were declassified and published in Arnold's history. It appears from Corner's account that there was a personality clash on 2 December 1955, and that Ward, who was so slow and incredibly diffident in presenting his design and arguments to Penney, that his design was simply dismissed as too complex and speculative to use.
In September 1955, Penney held a meeting with four Aldermaston staff, Sam Curran, John Corner, Herbert Pike and Ken Allen (Keith Roberts who had attended the August meeting, was also again present). Penney said he believed from 1954 Castle data acquired by AWRE long distance measurements that America had two types of megaton weapons: two-stagers where a fission bomb or "Tom" releases radiation which compresses a secondary U235 fission device called a "Dick" yielding around 1 megaton, and three-staged devices in which a third (thermonuclear) stage "Harry" was added, yielding about 10 megatons. Herbert Pike, who was present, explained this to Lorna Arnold in his 9 June 1995 letter: "The names Tom, Dick and Harry originated when it was thought that a simple fission device was inadequate for compressing thermonuclear fuel, but could be used to implode a much more powerful U235 device. This idea was soon dropped, but the names remained."
Penney knew from UK collected fallout samples from the first 400 kt Russian single-stage externally boosted thermonuclear test of 1953, that external fissile core fusion boosting was possible in single-stage devices, so this was also studied at Aldermaston and proof tested in 1956 at the two shots of Operation Mosiac, Monte Bello. The Aldermaston physicist Keith Roberts in October 1955 wrote a paper on internal and external boosting, arguing for the use of a mixture of the solid salts lithium deuteride and lithium tritide (LiD and LiT) in a hollow fissile core for internal boosting (rather than the use of D+T gas, used to boost cores of some American weapons since 1951). This boosted device was "Orange Herald". For external boosting, a device called "Green Bamboo," Roberts suggested a layer of LiD between the fissile core and its uranium tamper: "to catch neutrons as they come out of the core, convert them into 14 Mev neutrons, and burn up the tamper."
The first problem with this Green Bamboo idea is that LiD around the fissile core acts as a neutron absorber (instead of a reflector like uranium or beryllium), and therefore increases the critical mass needed (or the amount of compression needed, requiring more conventional explosives around the pusher to squeeze it plus everything else such as LiD to higher density, just to achieve core supercriticality). The second problem is that the fusion rate in the external LiD layer is determined by its compression, and this is weaker for the core which is pushing something outwards in all directions and thereby dispersing it, than if you are compressing it (when it has nowhere to go but in upon itself). By the time the core begins to expand, the inward compressive shock wave from the conventional explosives has long since passed through the tamper and into the core, where it reflects. There is a small inertial retardation to outward LiD dispersion from core expansion, due to the heavy uranium tamper surrounding it, but numerically this is like using layer of duct tape to delay a hand grenade exploding. The inertial delaying effect of the tamper is simply too small. The tamper's expansion-delay time is trivial unless the uranium tamper is made so thick that you need many tons of conventional explosives to compress the mamoth device in the first place. The bomb would then be undeliverably large and heavy. Nevertheless, since the Russians had used this scheme as "Joe 4" in August 1953, it was investigated by the UK.
Ken Allen in his 14 February 1956 Nuclear Physics Branch Note AWRE-NPBN 56/1 estimated that the externally boosted single-stage Green Bamboo design would have an efficiency of U235 fission 5-10 times less than a two-stage radiation coupled bomb in which the second stage is U235 imploded by x-rays from the primary stage. Two externally boosted bombs of this type were tested during Operation Mosiac at Monte Bello: G1 with a lead tamper which yielded 15 kt, and the larger G2 containing a uranium tamper which yielded 60 kt. It was found that the external boosting only produced "a few percent change in the yield."
AWRE also gained data from the analysis of long-range blast and fallout from the 5 and 22 November 1955 Russian nuclear tests, Joe 18 (215 kt, a likely primary stage test for the H-bomb) and Joe 19 (1.6 megatons, the first Russian two-stage test). When the isotopic composition of the uranium in the fallout from Joe 19, the 1.6 megaton test, was determined, it contained large amounts of uranium-233: "much too large to be accounted for by fast neutron reactions on uranium-235. The most probably explanation the british representatives could advance was that the Soviet weaponeers had used uranium-233 to differentiate between the behaviour of uranium components in two separate parts of the test device. This interpretation clarified British ideas on the mechanism of a two-stage device."
Penney during a 15 March 1956 meeting with Cook, designed a three-stage "Green Granite" bomb, with a steel clyindrical casing, a fission primary "Tom", a lithium deuteride internally boosted large U235 fissile secondary spherical stage "Dick", and a final stage "Harry" consisting simply of a small unboosted U235 core surrounded by a thick LiD shell and then a thick outer U238 tamper. However, on 4 April 1955 Penney simplified this to just two stages (the primary and final stage), which was justified by a report by R. A. Scriven of the theoretical physics division of AWRE. The shortened version of Green Granite was to be called Short Granite. Arnold describes the result as a very modern design: "This was not the design used for the Granites fired as Grapple (they had many shells in Dick), but seems to resemble the simpler [more successful, 1.8 megatons] Grapple X device."
But, instead of stopping there, a disastrous "Alarm Clock" type many-shelled (and thus Rayleigh-Taylor instability prone) secondary stage for Short Granite was then designed on 27 April 1956. Some 14 concentric thin shells ranging in thickness from 0.034 to 0.971 inch, alternating between low density LiD and high density U, first proposed by Ken Allen in his paper dated 14 February 1956, were in the secondary of Short Granite, and it would require poor nuclear test results to kill them off and return to the simplicity of the 4 April 1955 design for Grapple X. Immediately after Short Granite yielded 300 kt, Penney tried to improve that design in a new bomb, Purple Granite, identical to Short Granite apart from adding "extra U235 and with the outer layer replaced by aluminium". This yielded even less energy, just 200 kt, poving that the low density outer shell of aluminium produced Taylor instability when compressing the denser U235 layers within it. The Granite design fault was Taylor instability in the many layers of varying densities, a fault easily corrected.
John Corner summarized the situation in his "History of British R&D", given to America on the second day of the first official postwar UK-USA nuclear weapons design collaboration conference, 28 August 1958: "By late 1955, we were working on a simple system by which a trigger bomb and a thermonuclear bomb were placed inside a common outer case, with a radiation-transmitting material surrounding them."
At shots 1 and 2 of Operation Antler at Maralinga, Australia, in 1957, full two-stage weapons with standard primaries but inert (lead and cobalt) secondaries were tested. Cobalt-60 production in the secondary stage acted as a diagnostic tracer to determine neutron exposure from the primary stage, determining the neutron shielding required to prevent secondary pre-initiation.
After the low 300 kt and 200 kt yields of Short Granite and Purple Granite, which had low yield 30 kt primaries, an improved 45 kt primary employing a beryllium tamper was developed for Grapple X and further H-bombs. Aditionally, even the plastic foam filling was replaced by air to disperse X-rays around the secondary in successful Grapple Z: "Various ideas were discussed ... reducing the amount of filling in the casing ... It might even be possible to eliminate the filling altogether. Might not an air gap transport enough energy from the Tom to implode the Dick? This idea was later to be tried successfully at Grapple Z."
The physics of the detonation of the successful 1.8 megaton Grapple X on 8 November 1957 are described in detail by Arnold (2001, pp160-161). Grapple X was a Short Granite-sized double bomb but containing the improved Red Beard beryllium tamper composite core primary with a Po210-Be Urchin neutron initiator yielding 45 kt, and a simplified three layer secondary stage (U235 core, Li6D layer and U tamper). Arnold states the secondary stage was compressed to 5% of its original volume within 2 microseconds. The yield at 1.8 megatons was 80% greater than the predicted 1 megaton. (Arnold on p238 quotes Corner's statement that IBM 704 simulation of Grapple X predicted a 25-fold secondary volume compression.)
The next test, Grapple Y on 28 April 1958, the largest UK nuclear test ever conducted at 3 megatons, was K. W. Allen's idea to change the secondary design by reducing the U235 core to make more room for LiD which is easier to compress than U235, replacing most of the Li6D with a natural LiD, containing less lithium-6 and more lithium-7 (which actually has a higher cross-section for tritium production than lithium-6, when struck by the high energy 14.1 MeV neutrons produced to T+D fusion), and replacing the outer U shell with thorium: "Reducing the uranium-235 would make greater compression possible." (Arnold, p167.) Reducing the amount of dense fissile material in the secondary to increase its compression may sound superficially counter-intuitive, but computer calculations plus actual nuclear testing proved it to be true! It was dropped from a Valiant flying at 46,000 feet, exploding 53 seconds later at 8,000 feet altitude.
The final UK thermonuclear tests, Grapple Z, were the first two stage UK weapons to use primary stage boosting, not to increase their efficiency but to produce a similar ~50 kt yield with less fissile material. The only reason the UK wanted fusion boosted primary stages was to get the same yield with less plutonium, not for reasons of efficiency, but to so-called radiation immunity or "RI", when Moscow deployed defensive neutron bombs to melt down the fissile material of incoming warheads. This neutron multiplication problem for large fissile cores had been discovered at AWRE by K. V. Roberts and J. B. Taylor in early 1956.
External neutron initiators had first been used for the large 700 kt single-stage internally boosted Orange Herald test in 1957, a hollow core U235 bomb with a "very thin HE [high explosive] layer". However, Arnold reports that this shot only achieve the predicted boosted yield, so that boosting failed to achieve anything. This was the second failure of boosting for the UK, since Dr John Corner's 28 August 1958 report at the UK-USA bilateral Sandia meeting (Arnold's Appendix 3, at p239) states that the UK wanted to: "boost ordinary kiloton weapons with the aid of a gram or two of T. This first amount of T was therefore put into one of the weapons to be fired at Buffalo [Maralinga, 1956]. Unfortunately, the Buffalo weapons use a central initiator, and the presence of the deutero-tritide in the centre of the fissile core lowered the unboosted yield by a factor of order 2. ... This reluctance to redesign completely a weapon for the use of T persisted into 1957, when T was used on a fairly massive scale ... without on balance, improving on the result we would have got if a core had been used which contained no tritide (and no empty space for tritide). The desire to develop a strong source weapon [neutron hardened primary] ... led to a study of hollow gadgets. ... It was found theoretically that such a weapon would be extremely suitable for boosting with T, either as a deutero-tritide or as a gas. This has led to the [solid LiD + LiT boosted, 24 kt] Pendant and [T + D gas boosted, 25 kt] Burgee rounds."
The UK was so desperate to overcome neutron vulnerability, Arnold states on p181, that the UK decided to overcome the problem by using a double-primary system to compress a secondary: "This other round, to be tried if [solid LiD + LiT boosted] Pendant failed, was a novel concept - a triple, or three-stage, bomb which would, in effect, have two small, immune primaries with a combined yield sufficient to ignite thermonuclear fuel in the third component." In other words, the UK seriously considered testing a double-primary weapon, very similar to the Russian "Project 49" weapons first tested in February 1958, simply in order to reduce fissile core sizes to overcome neutron vulnerability to defensive ABMs.
The long held UK obsession with solid fissile cores is due to the fact that they were originally invented at Los Alamos by British Mission physicist Peierls, before being developed by Christy and named after him. Likewise, British Mission physicist James Tuck, who had been the physics assistant to Churchill's adviser Professor Lindemann, introduced the explosive lens system - adapted from British explosives research - to the implosion bomb, as well as working on Bethe on the Po210-Be central initiator in the core. These UK developments became hardened orthodoxy Gospel at AWRE - hence the proverb, if it ain't broke, don't fix it - until the neutron vulnerability forced the change to hollow cores and external neutron initiators. Arnold quotes Corner in her endnote 12 on p261: "... Corner was greatly impressed by the speed of the American development, from the Ulam-Teller breakthrough to the Mike shot. He thought the British lost too much time 'piddling about' (interview, March 1995)".
In the event, both solid boosted Pendant and gas boosted Burgee neutron-hard primaries worked during Grapple Z, so the double-primary design was never tested by the UK. The research done on it, howver, throws light on the Russian decision to use it, particularly as gives a compact neutron-hard thermonuclear weapon which requires no tritium for boosting (it is unboosted), an advantage for avoiding replenishment due to the 12.3 years half life of tritium! The two high yield UK atmospheric tests during Grapple Z in 1958 were 1.21 megaton Flagpole (a scaled down version of the highly successful 3 megaton Grapple Y bomb which used mostly natural unenriched lithium deuteride and an unboosted Indigo Hammer primary stage), and Halliard 1, a heavy cased triple-bomb which had a predicted yield of 750 kt but yielded 800 kt.
UK Prime Minister Harold Macmillan noted in his diary entry of 1 September 1958 (published in 1971 as "Riding the Storm 1956-1959", at page 563): "In some respects we are as far and even further advanced in the art than our American friends. They thought interchange of information would be all give. They are keen that we should complete our series, especially the last megaton [the triple-bomb Halliard 1, fired on 11 September 1958], the character of which is novel and of deep interest to them." In fact, America made the UK's testing of Halliard 1 a condition for transmission of America's 1.1 megaton Mk 28 and 400 kt Mk 47 data (Mac had wanted to scrap Halliard 1 testing, as part of an international testing moratorium).
Arnold continues to document the exchanges of nuclear warhead designs: "On 17-18 November [1958] in a meeting at Aldermaston on exchange of nuclear weapons design information, Penney and his senior staff met ... Brigadier-General Starbird, Norris Bradbury and Edward Teller. They brought up to date ... the Livermore TUBA design for a double bomb with a spherical secondary, which Teller said was very similar to British designs ... Pike and Schofeld, visiting Los Alamos and Livermore in February 1959 to discuss weapon pysics ... noted that both the American laboratories had done calculations on the Grapple Z Flagpole shot [the scaled-down 3 megaton Grapple Y success, with low-enrichment lithium and reduced U235 in the secondary stage], and had predicted substantially the same fusion and fission yields as had Corner's staff." The American Mk28 became the UK's megaton Red Snow.
Arnold's book finally, at page 227, addresses the only aspect of the UK (or any other) nuclear weapons tests considered worthy of mention in "science" and "news" media: alleged cancer induced by radiation effects to personnel: "A very comprehensive study of 21,358 test participants (estimated at 85% of the total) and 22,333 controls was carried out by an independent expert team, led by the eminent epidemiologist Sir Rochard Doll. ... The study examined mortality rates, the incidence of leukemia and 26 other forms of cancer, and 15 other causes of death. It found that there was no significant difference between the participants and the controls ... The team detected little evidence to relate cancer incidence to recorded dose; indeed, incidence tended to DECREASE with higher recorded doses." The highest fallout radiation doses received in any UK test were over 25R, by Canberra fallout sampling aircrew who spent 11 minutes flying 6 times through the 1.21 megaton Flagpole test mushroom cloud at 53,700 feet altitude after their radiation meter malfunctioned! Because all the UK H-bombs were air bursts at altitudes of 2.2-2.8 km, there was no local fallout at Chrismas island. However, many personnel were close enough to receive relatively small doses of initial nuclear radiation, and were not provided with dosimeters or health checkups after some of the tests.
(Quotations and data from official historian Lorna Arnold, Britain and the H-Bomb, Palgrave, 2001.)
So even the formerly classified history of the first British H-bombs is now in the public domain. It is no good pretending that such information remains secret or even mysterious!
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